I am building one about the same dimensions: 14 length x 5.5 width x 7 tall
I was told mine would hold 2 pairs, but I am going to just have one for now, since this is my first pair.
I'm not sure if you have the pond yet or not, but I found an excellent oval-shaped pond at
Tractor Supply for less than $40. I originally bought a pond liner at Lowes, but it was way too thin and flimsy and plus it was like $60.
The one at
Tractor Supply is a rubbermaid one and it's THICK! It also has better dimensions and is shallower, which is a plus for me.
I'll edit my post with a link to my thread so you can see some of the recommendations i got on the flooring and a pic of my two liners. I took pics of both.
I currently dug out my shrubs and mulch and have just a clay bottom right now. I am going to put in a truckload of screened topsoil, which i believe should be sand, silt, and clay. I don't know the exact ratio of each, but it's probably 40/40/20 or even across the board.
If you have grass that is fine, but I saw a few posts that said it would be gone in about half a year with a pair or two ducks.
The zoo in my area has smooth/rounded pebble floors.
I have seen a few people recommend small pea gravel with sand, sand, and of course recommendations against sand and gravel.
It's a little confusing.
Mine is fairly sheltered in the spot i plant to set it up, so I am not going to do the roof i originally planned. It is well-shaded and i want what little sunlight that can penetrate it to get there.
I am going to make a little duck shed/shelter that will have 3 walls of treated plywood with a roof though for nesting, sleeping, or if they just want to go in there.
A majority of people do recommend putting smooth gravel around and under areas that will have water, like a water dish, and pond.
I bought some jade pebbles to put around my pond and then i bought some moon rock gravel.
I plan to post some pics of the gravel in my thread later this weekend, since i need to update all the supplies i bought so far.
Edit:
Here is the link to my thread with a few recommendations:
https://www.backyardchickens.com/forum/viewtopic.php?id=326040
Edit 2:
Forgot to add, I had to ditch grass for mine, because sadly I just added the scott's fertilizer to my entire lawn about 3 months ago. Someone posted in another thread that Scott's recommended not transplanting, feeding, or using grass in a pet enclosure or let them graze on it for one year if it was fed with their grass fertilizer. So if your grass area was fertilized, you might want to just remove it. I had a thin strip in my area and just removed it along with a few inches of the dirt to be safe.
